mctaggart



A. L. McTAGGART.

PARALLEL RULEH.

APPLICATION FILED FEB. 24. 1917.

'1 322,592. Patented Nov. 1919.

T FFIC i ANGUS L. MCTAGGART, OF PITTSBURGH, PENNSYLVANIA.

PARALLEL-RULER.

To all whom it may concern:

Be it known that I, ANGUS L. MoTAGcaRT, a subject of the King of England, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Parallel-Rulers, of which the following is a specification.

The principal objects of my invention are to provide a simple and efficient parallel motion ruler to enable straight and parallel lines to be readily produced; a ruler positive in its action and easily operated; a ruler having clamping or locking means designed to fixedly position the straight-edge of the ruler in any desired position throughout its length of travel; and a ruler constructed to permit the use of a continuous length of drawing paper and to prevent contact of the straight-edge with drawin paper during the travel of the edge over t e paper.

In the accompanying drawing, which illustrates an application of my invention,

Figure 1 is a plan view, broken away at the center of a parallel ruler embodying my invention.

Fig. 2 is an end elevational View.

Fig. 3 is a sectional view taken on line 33 of Fig. 1.

Fig. 4 is a detail sectional view, the section being taken on line 4 4c of Fig. 3.

Referring to the drawing, my parallelruler is designed to be used in connection With a suitable table or drawing-board 1', and is operable on a track elevated a slight distance from the board. As illustrated and as preferred, the track comprises two rackbars 3 secured to the board in parallel relation by means of screws 4L passed through the rack-bars and through apertured spac-, ing members 5. The purpose of the members 5 is to provide a desired space between the board and the under face a of each rack- .bar, a space sufiicient to permit travel of the Specification of Letters Patent.

Patented Nov. 25, 1919.

Application filed February 24, 1917. Serial No. 150,78.

track. As illustrated, these means include a pair of housings or blocks 7 each being disposed adjacent to the respective rackbars, a rotatable shaft 8 journaled in ball or other suitable bearings 9 mounted in the blocks 7 pinions 10, one fixed on each end of shaft 8, and ring members 11, the latter being rigidly secured to shaft 8 and adapted to revolve therewith. The straight-edge 6 extends from one block to the other and slightly beyond the block a sufficient distance to engage the face a of the respective rackbars. Said straight-edge is secured adjacent its ends to the bottom faces of the blocks by means of countersunk bolts 12 and nuts 13, the former being passed through the straight-edge and a portion of the block and terminating in recesses 14: formed in the blocks.

15 designates a pair of thumb screws, each being adapted to cooperate with one of the rotatable rings 11, for the purpose of locking the straight-edge at any desired point within the length of its travel on the track.

What I claim is 1. In a parallel ruler, the combination with a table or board, of a pair of spacedapart parallel rack-bars, means for spacing the under faces of said bars away from the table or board, a straight-edge having end portions extending under the raclcbars, a rotatable shaft having pinions thereon cooperating with the rack-bars, movable blocks through which the ends of the shaft project, shaft bearings in the blocks, a ring fixedly mounted on the shaft within a block, locking means cooperating with the ring, and means for securing the straight edge to the blocks.

2. In a parallel ruler, the combination with a table or board, of a pair of spacedapart parallel rack-bars, means for spacing the under faces of said bars away from the table or board to permit drawing paper to be inserted between the board and the under faces of said rack-bars, a straightedge, a rotatable shaft having inions thereon cooperating with the raclE-bars, blocks through which the ends of the shaft project, shaft hearings in the blocks, a ring fixedly mounted on the shaft Within a block, looking means cooperating with the ring, said blocks movable with the shaft, and means for securing the straight-edge to the blocks.

3.. lln a parallel ruler, the combination with a table or board, of a track, a support for the track, means for spacing the track away from its support to permit drawing paper to be of the trac and the board or table, a straight edge, a traveling'carrier mechanism mounted on the track, said carrier mechanism including a. rotata'ble shaft, members mounted thereon and engaging the track, and means carried-by the shaft to which the straight edge is attached, said latter means including blocks having shaft bearings thereon.

4. In a parallel ruler, the combination with a table or board, of a track comprisingspaced-apart parallel elevated rack-bars, a straight-edge having endportions extending under the elevated rack-bars, and a traveling carrier mechanism mounted on.

the track, said carrier mechanism including a rotatable shaft, pinions rigidly mounted thereon, locking means for preventing travel of the carrier and engaging the rack-bars, and means carried by the shaft to which the straight-edge is attached. "a

5. In a parallel rfiler, the combination with a drawing-board, of a pair of spaced-apart parallel rack-bars secured to said board, means for spacing the under faces of said bars away from the board, a rotatable shaft,

blocks carried by the shaft, and disposed adjacent to the rack-bars, pinions on the shaft cooperating with the rack-bars, rings on the shaft and rotatable therewith, said rings each being located within a block, locking means carried by the blocks and cooperating with said rings, a straight-edge secured to assed between the under faces the blocks, said strai ht-edge extending from one rack-bar to t e other and having its end portions arranged to make contact with the under faces of the rack-bars.

board, said straight edge having end portions extending under the rack bars.

7 .In a device of the character described, the combination with a drawing-board, of an elevated track includin a pair of parallel rack-bars secured to t e board, means for spacing the under faces of said bars away from the board, travel means including a rotatable shaft having pinions thereon cooperating with the rack-bars, straightedge supporting means spaced from the -board and carried by the travel means, and

a straightedge secured to its supporting means and spaced from the board, and having end portions extending under the rack bars.

In testimony whereof I affix my signature in presence of two witnesses.

ANGUS L. 'MCTAGGART.

Witnesses W. G. Doomr'rm, Amcn'B. DICE. 

